Yoga has an abundance of benefits for the mind and body. As someone who teaches your practices yoga yourself you may often hear claims about yogas impact, but are they all true?

In these post we explore some common claims about yoga to cut the fact from the fiction, adapted from The Physiology of Yoga.

FACT OR FICTION: Bad posture leads to poor breathing

Tight neck and chest muscles, such as the intercostal and pectoralis muscles, can restrict the free movement of the rib cage. Additionally, if you are slouching forward, your abdominal organs will be more compacted and not able to move as freely as the diaphragm descends. For this same reason, we can sometimes find it difficult to breathe deeply after a big meal; the abdominal contents cannot be as easily displaced as before the meal. The same is the case for a pregnant woman where the abdomen cannot be moved very much because of the immovable bundle of joy within.

A small number of studies, including one from South Korea (Jung et al. 2016), have connected use of electronics including smartphones and laptops with forward head posture (called /text neck/) and found a connection between forward head posture and reduced lung function.

Dimitriadis and colleagues (2014) found that people with chronic neck pain do not have optimal lung function. The authors found a correlation between compromised lung function, weak neck muscles, and kinesiophobia, or fear of movement. They suggest that both pain and kinesiophobia may alter neck biomechanics, further contributing to the development of respiratory dysfunction.

So, the literature might support the idea that our sitting and standing posture, including our neck position, can affect breathing but probably not to the extent that many blogs might make you believe. Also, this does not mean that slumping onto the sofa is inherently bad; sometimes nothing can be better after a long day. But every now and again, it is certainly a good idea to check in with how you are breathing and how you are feeling. After all, what does yoga teach us if not awareness of breath and self?

FACT OR FICTION: Heavy sweating during hot yoga detoxifies the body

Detoxification is the physiological processes through which the body identifies, neutralizes, and eliminates toxic substances and metabolic byproducts. Detoxification is an essential part of homeostasis, and our bodies naturally possess the capacity to perform these processes very effectively. Without an effective detoxification system, we would be very unwell.

Sweat glands are often perceived to play an important excretory function, similar to that of the kidneys. However, in a comprehensive review, Baker (2019) concluded that the role of the sweat glands in eliminating waste products and toxicants from the body seems to be minor compared with other avenues of breakdown (liver) and excretion (kidneys and gastrointestinal tract). Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body (e.g., concentrations in sweat greater than that of blood) may be an artifact of methodological issues rather than evidence for selective transport.

So, it appears that heavy sweating in a hot yoga class or in a sauna might not help us to relinquish all those perceived toxins after all. However, practicing yoga as part of a healthy lifestyle will allow our kidneys, liver, and gastrointestinal tracts to continue to work optimally.

FACT OR FICTION: Kapalabhati stops the aging process

Kapalabhati is a breathing exercise where the practitioner makes successive, rapid, forceful exhalations through the nose or, less commonly, the mouth. . It is performed by exhaling forcefully and then inhaling passively. Hence, the inhalation is slightly longer than the exhalation and an inhale–exhale cycle might last one second or even less.

As this exercise requires a rapid and sustained effort by the abdominal muscles, the abdominals might experience increased tone. Similarly, muscular contractions release heat, so it stands that performing kapalabhati might generate thermogenesis (heat production).

Additionally, kapalabhati demands a sustained focus of the mind, thus bringing the mind’s awareness to the breath. Finally, as it is a form of controlled hyperventilation, kapalabhati likely makes longer breath holds possible immediately following the exercise as carbon dioxide is off-loaded.

Practicing kapalabhati likely has other benefits, such as creating a feeling of invigoration, but it is not—and cannot be—a panacea for all ailments. As for kapalabhati stopping the aging process, it is probably as effective as snake oil.

Read more about how yoga can impact our health and wellbeing in The Physiology of Yoga.

References

• Baker, L. 2019. “Physiology of Sweat Gland Function: The Roles of Sweating and Sweat Composition in Human Health.” Temperature (Austin) 6 (3): 211-259.
• Dimitriadis, Z., E. Kapreli, N. Strimpakos, and J. Oldham. 2014. “Pulmonary Function of Patients With Chronic Neck Pain: A Spirometry Study.” Respiratory Care 59 (4): 543-549.
• Jung, S.I., N.K. Lee, K.W. Kang, K. Kim, and D.Y. Lee. 2016. The Effect of Smartphone Usage Time on Posture and Respiratory Function. Journal of Physical Therapy Science 28 (1): 186-189. https://doi.org/10.1589/jpts.28.186.

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